Clam shell excavator

ABSTRACT

A supporting frame cars a pair of pivoted arms which are movable toward and away from each other by fluid operators reacting between the arms nd the frame. A pair of complemental bucket members are pivoted to lower end of the respective arms for movement toward and away from each other independently of the pivotal movement of the arms. The bucket members are moved by fluid operators reacting between the arms and the bucket members. A suction pipe extends through the frame between the arms for picking up material loosened by the bucket members.

United States Patent Piccagli 51 Sept. 26, 1972 [54] CLAM SHELL EXCAVATOR [72] inventor: Ugo Plccagli, 14202 Hay Meadow Dr., Apt. 167, Dallas, Tex. 75240 [22] Filed: Oct. 13, 1970 [21] Appl. No.: 80,357

[30] Foreign Application Priority Data Sept. 10, 1970 Canada ..092866 [52] US. Cl. ..37/187, 37/71, 37/188 [51] Int. Cl ..B66c 3/02 [58] Field of Search ..37/l87, 71, 188

[56] References Cited UNITED STATES PATENTS 2,889,642 6/1959 Stein ..37/7l UX FOREIGN PATENTS OR APPLICATIONS 1,454,963 8/ 1966 France ..1 87/ Primary Examiner-Robert E. Pulfry Assistant Examiner-Clifford D. Crowder Auorney-Fetherstonhaugh & Co.

[5 7 ABSTRACT A supporting frame cars a pair of pivoted arms which are movable toward and away from each other by fluid operators reacting between the arms nd the frame. A pair of complemental bucket members are pivoted to lower end of the respective arms for movement toward and away from each other independently of the pivotal movement of the arms. The bucket members are moved by fluid operators reacting between the arms and the bucket members. A suction pipe extends through the frame between the arms for picking up material loosened by the bucket members.

2 Claims pr wi s Fi q a PATENTEDSEPZS I972 SHEET 1 0F 3 INVENTOR Ugo PICCAGLI t PA TENT'AGENTS PATENTEDsms I972 SHEET 3 UF 3 INVENTOR Ugo PICCAGLI PATENT AGENTS CLAM SHELL EXCAVATOR This invention relates to new and useful improvements in excavation equipment, and in particular the invention concerns itself with clam shells which are used in large excavation and constructionprojects.

Conventional clam shells commonly used for large excavations have a frame and a pair of clams or buckets which are movable toward and away from each other about pivots on the frame. In operation the frame is lowered and the clams are brought together to pick up material which is to be excavated. In large construction jobs where extremelybig and cumbersome clams are used, the pivotal movement which brings them together results in a half-moon form of excavation and material is not picked up with each closing of the clams. In other words, when the bottom of the excavation is reached, some material is left in the opposite comers which cannot be reached by the clams and must therefore be excavated by some other means.

Another serious disadvantage of conventional clam shells is that the clams or buckets are brought together at the same time and close relative to each other. Thus, when the clam shell is lowered into a deep excavation, the operator cannot see how the device is working and if one of the buckets strikes some object which prevents it from closing properly, the whole device will tilt about the obstruction before the other bucket comes close to the obstructed bucket. This, of course, starts off a deviation which, if continued, seriously interferes with excavation in a perpendicular direction as intended.

The principal object of the present invention is to provide a novel and greatly improved clam shell which effectively minimizes, if not altogether overcomes, the above outlined disadvantages of conventional clam shells. As such, the invention provides a supporting frame having a pair of arms pivoted thereto and a pair of bucket members pivoted to the respective arms. Fluid operators independently move the arms toward or away from each other, and other fluid operators move the bucket members independently toward or away from each other and also independently of the movement of the arms. The arrangement is such that the bucket members may be pre-positioned so as to avoid leaving large amounts of material in the corners of the excavation. Moreover, the independent actuation of the bucket members and armsfacilitates excavation in the vertical direction even if one of the bucket members encounters an obstruction.

It is another object of the present invention to provide a clam shell which is well suited for excavation of silt and sand. Under such conditions a suction pipe is extended downwardly close to the clam shells and the bucket members are operated with the arms spread far apart. This loosens the sand and silt permitting it to be pumped away through the suction pipe.

With the foregoing more important objects and features in view and such other objects and features which may become apparentas this specification proceeds, the invention will be understood from the following description taken in conjunction with the accompanying drawings, wherein like characters of reference designate like parts and wherein:

FIG. 1 is a side elevational view of the clam shell of the invention;

FIG. 2 is an end elevational view thereof taken in the direction of the arrow 2 in FIG. 1; and

FIGS. 3, 4 and 5 are diagrammatic views on a reduced scale, showing the clam shell in the open, partially closed and fully closed positions, respectively.

Referring now to the accompanying drawings in detail, the clam shell of the invention is designated generally by the numeral 10 and comprises a supporting frame 11 having a pair of arms 12, 13 depending therefrom, these arms being pivotally connected to the frame by suitable pivots l4, 15, respectively, for movement of the arms toward or away from each other. The arms l2, 13 are actuated by a pair of fluid operators l6, 17, respectively, which react between the arms and the frame 11. As such the fluid operators l6, 17 may be disposed within the frame and pivoted thereto as at 18, 19, respectively, and pivoted to the respective arms l2, 13 as at 20, 21. Conveniently, the arms 12, 13 may have a substantially triangular shape, as shown.

A pair of complemental bucket members 24, 25 are pivoted as at 26, 27 to the lower ends of the respective arms 12, 13 for pivotal movement of the bucket members toward or away from each other independently of the pivotal movement of the arms. The bucket members are actuated by a pair of fluid operators 22, 23 which react between the bucket members and the respective arms. The fluid operators 22, 23 are pivoted to the bucket members 24, 25 as at 2,8, 29, respectively, and are pivoted to the respective arms l2, 13 by the same pivots l4, 15 which connect the arms to the frame 11. It will be understood that pivots other than the pivots 14, 15 may connect the fluid operators 22, 23 to the respective arms 12, 13.

Each of the bucket members 24, 25 has a curved bottom wall 31 and two sector-shaped side walls 32, the latter being provided at their edges with toothed cutter bars 33 to assist in breaking action of the bucket member in material to be excavated. Also, teeth 34 are provided on and project from the bottom wall 31 to assist in breaking up the material.

The operation of the invention will be understood from FIGS. 3-5 where FIG. 3 shows the clam shell in its open position wherein the arms 12, 13 are drawn apart by the fluid operators l6, l7 and the bucket members 24, 25 are separated and swung upwardly by the fluid operators 22, 23. In this position the clam shell may be lowered by cables, or the like (not shown) to the material to be excavated, it being noted that at this stage the cutter bars 33 of the bucket members are'substantially horizontal while the teeth 34 are substantially vertical, so that the cutter bars and teeth my penetrate and break up the material as the clam shell is lowered.

With this accomplished, the fluid operators 22, 23 are actuated so as to pivotally move the bucket members 24, 25 about the pivots 26, 27 to the position shown in FIG. 4, wherein the cutter bars 33 are substantially in line with the pivots 14, 26 and 15, 27, or in other words, in substantial alignment with the inner edges of the arms 12, 13. After the operator has noticed that the two bucket members have completed their inward movement to this position as shown in FIG. 4, the fluid operators l6, 17 are actuated to move the arms 12, 13 toward each other, thus also bringing the bucket members 24, 25 toward each other in the fully closed position of the clam shell shown in FIG. 5.

In this position the cutter bars 33 are substantially vertical and .the teeth 34 of the two bucket members are interfitted.

It is to be particularly noted that the fluid operators 22, 23 are operable entirely independently of the fluid operators 16, 17, and vice versa. Thus, when the bucket members 24, 25 are moved from the FIG. 3 position to the FIG. 4 position by actuation of the fluid operators 22, 23, such movement takes place only about the pivots 26, 27 and the arms 12, 13 remain in the same position relative to the frame 11. Then, when the arms 12, 13 are moved from the FIG. 4 position to the FIG. 5 position by actuation of the fluid operators 16, 17, such movement takes place only about the pivots 14, and the bucket members 24, 25 remain in the same position relative to the arms l2, 13, although they move bodily with the arms. 12, 13 may be pivotally moved by itself. With this independent control, the operator of the machine may readily notice when any one of the four fluid operators has not completed its movement because of some encountered obstruction, and the operator may then quickly actuate an appropriate one or more of the other fluid operators so as to maintain the machine on an even keel and prevent deviation from the intended course of excavation before it is too late for corrective measures to be taken.

The arrangement of the invention facilitates use of a clam shell which is capable of taking a much larger bite than conventional devices of this type. For example, the clam shell may take a bite 15 feet wide, which may be desirable in constructing a retaining wall or forming a long, narrow trench. In a conventional clam shell capable of taking a bite 15 feet wide, the bucket members would have to be about 7% feet deep, and in pivoting to their closed position such bucket members would leave a considerable amount of unexcavated material at the opposite comers of the excavation. However, with the clam shell of the invention, the bucket members may be relatively shallow since they pivot about the points 26,27 while the arms 12, 13 are still separated, so that when the arms are brought together, the bucket members travel almost horizontally toward their closed position. Thus, the amount of unexcavated material left in the corners is very small indeed.

The invention, in addition to its general utility, is well suited for excavation of silt and sand. in such event the supporting frame 11 is provided with a suction pipe 35 which is connected to a suitable pump (not shown), the

pipe 35 extending downwardly through the frame 11 between the arms 12, 13. When the clam shell is used in this manner, the arms 12, 13 are spread apart and the bucket members 24, 25 are opened as in FIG. 4, whereupon the fluid operators 22, 23 are actuated to rock the bucket members about the pivots 26, 27. This action loosens the sand and silt so that it can be pumped away through the suction pipe 35, and at the same time a trench is created, the full width of the open clam shell. Without lifting the frame 11, the weight of the whole clam shell assists in the digging operation since it provides downward pressure for causing the bucket members to bite through the excavation material while the sand and silt are being pumped away).

hl e m the foregoing there has been descri ed and shown the preferred embodiment of the invention, various modifications and equivalents may be resorted to, within the spirit and scope of the invention as claimed.

What is claimed as new is:

1. A clam shell excavator, comprising in combination, a supporting frame having a central vertical axis, a pair of pivots provided on said frame adjacent to and at opposite sides of said central axis, a pair of downwardly tapered triangular anns having inner and outer upper corners and a lower corner, said arms being mounted by their inner upper corners on the respective pivots and extending downwardly from said frame, a first pair of fluid operators pivotally mounted within said frame at points remote from said central axis and outwardly beyond said pivots of said arms, said first pair of operators being connected to the outer upper corners of the arms for moving the latter toward and away from said central axis, a pair of complemental bucket members pivoted to the lower comers of the respective arms for movement of the bucket members toward and away from each other independently of the pivotal movement of said arms, and a second pair of fluid operators reacting between the pivots of said arms on said frame and said bucket members for moving the latter.

2. The device as defined in claim 1 together with a suction pipe extending through and projecting below said frame between said arms for picking up material loosened by movement of said bucket members. 

1. A clam shell excavator, comprising in combination, a supporting frame having a central vertical axis, a pair of pivots provided on said frame adjacent to and at opposite sides of said central axis, a pair of downwardly tapered triangular arms having inner and outer upper corners and a lower corner, said arms being mounted by their inner upper corners on the respective pivots and extending downwardly from said frame, a first pair of fluid operators pivotally mounted within said frame at points remote from said central axis and outwardly beyond said pivots of said arms, said first pair of operators being connected to the outer upper corners of the arms for moving the latter toward and away from said central axis, a pair of complemental bucket members pivoted to the lower corners of the respective arms for movement of the bucket members toward and away from each other independently of the pivotal movement of said arms, and a second pair of fluid operators reacting between the pivots of said arms on said frame and said bucket members for moving the latter.
 2. The device as defined in claim 1 together with a suction pipe extending through and projecting below said frame between said arms for picking up material loosened by movement of said bucket members. 